PHYS 3 Chapter Notes - Chapter 25.1-25.3: Four-Current, Electric Field, Phase Transition
Document Summary
25. 5 resistivity not a general description of all matter: ampere = the si unit of current. Si unit is: current density = the current per unit cross-sectional area. Units are: equation 25. 2: current though an area, equation 25. 4: vector current density, equation 25. 5: resistivity of a material: At a given temperature, iis a constant that does not depend on the value of: equation 25. 6: temperature dependence of resistivity: Is the temperature coefficient of resistivity first decreases smoothly, like that of any metal, but then at a certain critical temperature , Good conductors of electricity have larger conductivity than insulators. Superconductivity = a phenomenon in which as temperature decreases, the resistivity at. Ohmic resistors obey ohm"s law, and at a given temperature, current is proportional to. A nonohmic resistor does not obey ohm"s law voltage. 25. 3 resistance: equation 25. 7, equation 25. 8, resistance = the ratio of to for a particular conductor.
